Motor



June 7, 1966 J. N. MAZUR 3,254,570

MOTOR Filed March 26, 1964 2 Sheets-Sheet 1 JOSEPH N. MAZUR ATTORNEYSJune 7, 1966 .1. N. MAZUR 3,254,570

MOTOR Filed March 26, 1964 2 Sheets-Sheet 2 FIGS BY ATTORNEYS UnitedStates Patent 3,254,570 MOTOR Joseph N. Mazur, Kalamazoo, Mich, assignorto The lglew York Air Brake Company, a corporation of New ersey I FiledMar. 26, 1964, Ser. No. 354,987 3 Claims. (Cl. 91138) This inventionrelates to rotary hydraulic motors of the vane type having fiuidpressure biased vanes.

In motors'of this kind, it is common practice to vent the space in eachvane slot beneath the vane as the vane moves through the discharge orlow pressure zone. This allows the vane to be retracted freely by thecam ring and thus minimizes wear of the cam surface. However, it hasbeen found that use of this scheme sometimes causes fluctuations in thetorque output of the motor. 'This is attributable to the fact that asthe vane enters the discharge zone, the intervane working space behindit is still at a high pressure. Thus, when the space beneath the vane issuddenly vented, the pressure in the working space forces the vaneinward away from the cam ring.

The object of this invention is to provide an improved vane motorincluding means for eliminating the vane separation problem in theregion of the entrance to the discharge zone. According to thisinvention, the motor includes means for venting to the discharge zonethe intervane working space behind each vane as the vane approaches thatzone and before the space at the inner end of its vane slot is vented.This means is rendered effective after the intervane working spacebehind the vane is isolated from the high pressure inlet zone by thenext succeeding vane, and, therefore, it insures that the outer tip ofthe vane will not be subjected to a high pressure when its inner end isvented. Since the invention reduces the pressure that develops theinward directed force on the vane, it eliminates the vane separationproblem.

The preferred embodiment of the invention is described herein withreference to the accompanying drawings in which:

FIG. 1 is an axial sectional view of a double lobe vane motorincorporating the invention.

FIGVZ is an enlarged sectional view taken on line 2-2 of FIG. 1, some ofthe parts being broken away to show the front face of port plate 18.

FIG. 3 is a sectional view taken on line 33 of FIG. 1 showing the frontface of port plate 18'.

FIG. 4 is a view showing the back face of port plate 18.

FIG. 5 is an enlarged sectional view taken on line 5-5 of FIG. 2. 7

As shown in the drawings, the motor comprises a housing having separablesections 11 and 12 which are joined by bolts (not shown) and which areformed to receive and hold a motoring cartridge 13. The housing .isprovided with a pair of ports 14 and 15 and communicating manifolds 16and 17. Although either of the ports 14 and 15 may serve as the inletport depending upon the desired direction of motorrotation, it isassumed in this description that port .14 is the inlet port and thatport 15 is the discharge port.

Motoring cartridge 13 includes a pair of identical port plates 18 and18', a cam ring 19, and a rotor 21, and is held together by a pair ofdiametrically opposed bolts 22. The rotor 21 is connected in drivingrelation with shaft 23 by splines 24, and is formed with ten uniformlyspaced, radial slots 25 whose bases are defined by through cross bores26 and which receive sliding vanes 27. The

outer peripheral edges of the rotor are beveled at 28 to improve accessbetween the ports in port plates 18 and 18' and the intervane workingspaces. Vanes 27 are of the type described in Rosen Patent 2,393,223,granted January 15, 1946, and each includes a pair of identical leaves27a. The outside edges of the vane leaves are chamfered, as by tumbling,to define with the walls of the slots 25 and the port plates 18 and 18'a restricted passage 28 (see FIG. 5) at each side of the leaf. Thepurpose of these restricted passages will be explained ater.

The front face of port plate 18 contains two diametri-' cally opposedinlet ports 29 and 31 which extend through the port plate, and twodiametrically opposed, blind discharge ports 32 and 33; all of theseports being positioned radially to register with the intervane workingspaces. The angular distances between adjacent ends of the inlet ports29 and 31 and ,the discharge ports 32 and 33 are approximately equal tothe intervane interval, i.e., the angular distance between the trailingedge of one vane and the leading edge of the next succeeding vane. Inletports 29 and 31 communicate with kidney-shaped recesses 34 and 35,respectively, formed in the rear face of the port plate, and theserecesses in turn communicate with manifold 16 through the asymmetricflow valve 36. Valve 36 is of the same general type as the one describedin Stewart Patent 2,808,814 granted October 8, 1957, and serves torestrict flow from manifold 16 to recesses 34 and 35' and to permitsubstantially unrestricted flow in the reverse direction.

The front face of port plate 18 also contains eight equispaced vanebiasing ports 37, 38, 39 and 41-45 which are positioned radially toregister with the cross bores 26 in rotor 21. Biasing ports 37 and 38lie in the region of inlet ports 29 and.31, respectively, and areconnected with manifold 16 via bores 46 extending through. the portplate, whereas biasing ports 39 and 41 lie in the regions of dischargeports 32 and 33 and are blind. Biasing ports 42-45 also are blind butthey have inward extensions that communicate with a central opening inport plate 18. These ports receive fluid from manifold 16 via bores 46,annular groove 47 and the disk check valve 48.

Since port plates 18 and 18' are identical, their porting arrangements,in the assembled condition of cartridge 13, are reversed. Thus, theports 29, 31, 37 and 38' in port plate 18, which face the through ports29, 31, 37 and 38, respectively, in port plate 18, are blind, and theports 32, 33', 39 and 41', which face blind ports 32, 33, 39 and 41,respectively, open through the rear face of port plate 18' andcommunicate with manifold 17. The blind inlet ports 39 and 31' in plate18' are connected with the through ports 29 and 31 in plate 18 by twosets of passages 49 extending through cam ring 19, and the blinddischarge ports 32 and 33 in plate 18 are connected with the throughports 32' and 33' in plate 18 by two additional sets of passages 51extending through the cam ring. Only two of these interconnecting setsof passages 49 and 51 are illustrated in FIG. 2.

The cam surface 52 of a cam ring 19 comprises two diametrically opposedcircular arcs A and B of equal radius, two additional diametricallyopposed circular arcs (one being indicated at C in FIG. 2) of equalradius which are symmetrical about an axis normal to the axis thatbisects arcs A and B, and four blend curves or ramps 53 that join theadjacent ends of the four arcs. All four arcs have the same angularextent and all are centered Patented June 7, 1966 on the axis ofrotation. However, as will be evident from FIG. 2, the radius of arcs Aand B is greater than the radius of the remaining two arcs.

The motor described thus far is conventional. The improvement added bythis invention consists, in the case of the illustrated double-lobe,reversible motor, of four blind ports 5447 located in the front face ofport plate 18, and four corresponding ports 5'457 located in the frontface of port plate 18'. These eight ports are positioned radiallyintermediate the outer periphery of rotor 21 and the inner ends of thevanes 27 when the vanes are fully extended, and are positionedcircumferentially to span each van slot 25 just prior to registration ofthat siot with one of the low pressure biasing ports, i.e., the ports39, 39, 41 and 41' when the rotor is rotating in the direction of arrow58 in FIG. 2, and the ports 37, 37, 33 and 38 when the rotor is rotatingin the reverse direction. The intervane interval is so selected thatthose ports S s-S7 and 5-t-'57' immediately in advance of a dischargezone span a vane slot after the next succeeding vane has moved onto oneof the true arcs A and B andisolated the included intervane workingspace from the high pressure inlet zone.

Since the illustrated motor is of the double-lobe type, and thus affordstwo motoring cycles per revolution of rotor 21, the description ofoperation will be confined only to one cycle, namely the one involvinginlet ports 29 and 29' and discharge ports 32 and 32. As the rotor 21revolves in the direction of arrow 58 in FIG. 2, the vanes 27 in theinlet region move outward along a ramp 53 under the combined action ofcentrifugal force and the pressure force developed by the fluidtransmitted to the inner ends of the vane slots through high pressurebiasing ports 37 and 37'. Because of the presence of the asymmetric flowvalve 36, the pressure acting beneath the vanes 27 is higher than thepressure in the intervane working space so the vanes in this region aremaintained in sealing engagement with the cam ring. When a vane 27 movesonto the are A, the associated cross bore 26 moves out of registrationwith biasing ports 37 and 37' and then into registration with biasingports 43 and 43'. Since the ports 43 and 43 are part of a closed circuitwhich is maintained liquid-filled by flow from manifold 16 through checkvalve 48, the vanes will be held against the cam ring as they traveltoward the discharge region even though the pressure acting on theirouter ends is full inlet pressure.

As a vane 27 approaches the region of discharge ports 32 and 32, theassociated cross bore 26 is disconnected from biasing ports 43 and 43.Simultaneously, the port 55 spans the vane slot 25. The intervaneworking space behind the vane is now vented to the discharge regionthrough the restricted passages 28 at opposite sides of the trailingleaf 27a, the ports 55 and 55, and the restricted passages 28 atopposite sides of the leading leaf 27a. Although the flow along thispath is very small, being on the order of a drop of oil, it is adequate,in view of the incompressible nature of the oil and the fact that thefollowing vane has now isolated the intervane working space from theinlet region, to drop the pressure in the intervane working space.Continued movement of the rotor 21 brings the cross bore 26 intoregistration with the low pressure biasing ports 39 and 39'. Since thepressure at the outer end of the vane has been dissipated, the vane isnot shot inward but moves inward gradually under the action of ramp 53.

As stated previously, the drawings and description relate only to thepreferred embodiment of the invention. Since changes can be made in thestructure of this embodiment without departing from the inventiveconcept, the following claims should provide the sole measure of thescope of the invention.

What I claim is:

1. In a vane motor including inlet and discharge ports and a workingchamber having inlet and discharge zones that communicate respectivelywith the inlet and discharge ports, a rotor located in the workingchamber and containing a plurality of circumferentially spaced slots forreceiving sliding vanes, and a low pressure biasing port whichcommunicates with the space in each vane slot beneath the vane as thevane moves through the discharge zone, the improvement which comprisesmeans for venting to the discharge port the intervane working spacebehind each vane as the vane approaches the discharge zone and beforethe associated vane slot communicates with the low pressure biasingport.

2. In a vane motor including inlet and discharge ports and a workingchamber having inlet and discharge zones that communicate, respectively,with the inlet and discharge ports, a rotor located in the workingchamber and containing a plurality of circumferentially spaced slots forreceiving sliding vanes, transverse end wall means closing opposite endsof the working chamber, and a low pressure biasing port in thetransverse end wall means and positioned to communicate with the spacein each vane slot beneath the vane as the vane moves through thedischarge zones, the improvement which comprises (a) a vent port locatedin the transverse end wall means and positioned circumferentially inadvance of the low pressure biasing port and radially between the outerperiphery of the rotor and the inner ends of the vanes when the vanesare fully extended; and

(b) restricted passages associated with each vane and extending inwardfrom the intervane working spaces ahead of and behind the vane, thepassages registering with the vent port as a vane slot crosses that portto thereby vent the intervane working space behind the vane to thedischarge zone,

(c) the intervane spacing being so chosen that when the restrictedpassages of a vane register with the vent port the intervane workingspace behind the vane is isolated from the inlet zone by a succeedingvane.

3. In a vane motor including inlet and discharge ports and a workingchamber having inlet and discharge zones that communicate, respectively,with the inlet and discharge ports, a rotor located in the workingchamber and containing a plurality of circumferentially spaced slots forreceiving sliding vanes, transverse end wall means closing opposite endsof the working chamber, circumferentia-lly spaced low and high pressurebiasing ports located in the end wall means and positioned tocommunicate with the space in each vane slot beneath the vane as thevane moves through the discharge and inlet zones, respectively, and anintermediate pressure biasing port located in the end wall means andpositioned to communicate with the space in each vane slot beneath thevane when the vane is in a transition zone located between the inlet anddischarge zones, the improvement which comprises (a) a vent port locatedin the transverse end Wall means and positioned radially between theouter periphery of the rotor and the inner ends of the vanes when thevanes are fully extended, the vent port being positionedcircumferentially to span each vane slot after the slot is disconnectedfrom the intermediate pressure biasing port but before the slotcommunicates with the low pressure biasing port; and

(b) a pair of restricted passages associated with each vane and definedby portions of the vane, the vane slot and the transverse end wallmeans, one restricted passage being at the leading side of the vane andthe other restricted passage being at the trailing side of the vane,said restricted passages extending inward and serving to interconnectthe intervane working spaces ahead of and behind the vane through thevent port when the vane slot spans that port,

(c) the intervane spacing being so chosen that when a vane slot isspanned by the vent port the intervane working space behind that vane isisolated from the inlet zone by a succeeding vane.

References Cited by the Examiner UNITED STATES PATENTS 2,141,171 12/1938Centervall 103136 2,641,195 6/1953 Ferris 103--136 6 2,653,551 9/1953Rosaen 103136 2,809,593 10/1957 Klessig et al. '103136 3,014,431 12/1961Van den Bussche 91I35 3,102,494 9/ 1963 Adams 91-138 SAMUEL LEVINE,Primary Examiner.

JOSEPH H. BRANSON, JR., Examiner.

R. M. VARGO, Assistant Examiner.

1. IN A VANE MOTOR INCLUDING INLET AND DISCHARGE PORTS AND A WORKINGCHAMBER HAVING INLET AND DISCHARGE ZONES THAT COMMUNICATE RESPECTIVELYWITH THE INLET AN DISCHARGE PORTS, A ROTOR LOCATED IN THE WORKINGCHAMBER AND CONTAINING A PLURALITY OF CIRCUMFERENIALLY SPACED SLOTS FORRECEIVING SLIDING VANES, AND A LOW PRESSURE BIASING PORT WHICHCOMMUNICATES WITH THE SPACE IN EACH VANE SLOT BENEATH THE VANE AS THEVANE MOVES THROUGH THE DISCHARGE ZONE, THE IMPROVEMENT WHICH COMPRISESMEANS FOR VENTING TO THE DISCHARGE PORT THE INTERVANE WORKING SPACEBEHIND EACH VANE AS THE VANE APPROACHES THE DISCHARGE ZONE AND BEFORETHE ASSOCIATED VANE SLOT COMMUNICATES WITH THE LOW PRESSURE BIASINGPORT.